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Titolo:
The TRAPP complex is a nucleotide exchanger for Ypt1 and Ypt31/32
Autore:
Jones, S; Newman, C; Liu, FL; Segev, N;
Indirizzi:
Univ Illinois, Mol Biol Lab, Dept Biol Sci, Chicago, IL 60607 USA Univ Illinois Chicago IL USA 60607 , Dept Biol Sci, Chicago, IL 60607 USA
Titolo Testata:
MOLECULAR BIOLOGY OF THE CELL
fascicolo: 12, volume: 11, anno: 2000,
pagine: 4403 - 4411
SICI:
1059-1524(200012)11:12<4403:TTCIAN>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
YEAST SECRETORY PATHWAY; VESICULAR TRANSPORT; PROTEIN-TRANSPORT; SACCHAROMYCES-CEREVISIAE; GENETIC INTERACTIONS; GTPASE; GOLGI; RAS; MUTANTS; VESICLES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
42
Recensione:
Indirizzi per estratti:
Indirizzo: Segev, N Univ Illinois, Mol Biol Lab, Dept Biol Sci, Chicago, IL 60607 USAUniv Illinois Chicago IL USA 60607 ol Sci, Chicago, IL 60607 USA
Citazione:
S. Jones et al., "The TRAPP complex is a nucleotide exchanger for Ypt1 and Ypt31/32", MOL BIOL CE, 11(12), 2000, pp. 4403-4411

Abstract

Ln yeast, the Ypt1 GTPase is required for ER-to-cis-Golgi and cis-to-medial-Golgi protein transport, while Ypt31/32 are a functional pair of GTPases essential for exit from the trans-Golgi. We have previously identified a Ypt1 guanine nucleotide exchange factor (GEF) activity and characterized it as a large membrane-associated protein complex that localizes to the Golgi and can be extracted from the membrane by salt, but not by detergent. TRAPP is a large protein complex that is required for ER-to-Golgi transport and that has properties similar to those of Ypt1 GEF. Here we show that TRAPP has Ypt1 GEF activity. GST-tagged Bet3p or Bet5p, two of the TRAPP subunits, were expressed in yeast cells and were precipitated by glutathione-agarose (GA) beads. The resulting precipitates can stimulate both GDP release and GTP uptake by Ypt1p. The majority of the Ypt1 GEF activity associated with the GST-Bet3p precipitate has an apparent molecular weight of > 670 kDa, indicating that the GEF activity resides in the TRAPP complex. Surprisingly TRAPP can also stimulate nucleotide exchange on the Ypt31/32 GTPases, but noton Sec4p, a Ypt-family GTPase required for the last step of the exocytic pathway. Like the previously characterized Ypt1 GEF, the TRAPP Ypt1-GEF activity can be inhibited by the nucleotide-free Ypt1-D124N mutant protein. This mutant protein also inhibits the Ypt32 GEF activity of TRAPP. Coprecipitation and overexpression studies suggest that TRAPP can act as a GEF for Ypt1 and Ypt31/32 in vivo. These data suggest the exciting possibility that a GEF complex common to Ypt1 and Ypt31/32 might coordinate the function of these GTPases in entry into and exit from the Golgi.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 23/01/21 alle ore 09:58:14